Hi Mike, Thanks for your reply.
What I was doing was just trying to understand how the the data travels through normal fs or block layer, reaches iscsi and gets sent over the network, when there is a normal read()/write() request. So the function call trace I have found is not quite the normal path? Actually I'm still new to the kernel and the storage subsystem... So could you maybe tell me what I should look at to learn more about the normal code path of a read/write request? Or maybe point me to some online materials/books I can gain some understanding from? Thanks a lot! Jack On May 6, 10:56 am, Mike Christie <micha...@cs.wisc.edu> wrote: > On 05/05/2010 10:26 PM, Jack Z wrote: > > > Hi Mike, > > > Thank you for your help again. Following the guidance in your reply, I > > traced the kernel code a bit more and eventually found out a possible > > path for open-iscsi to get 4K pages in the scatterlist. > > > Kernel version: 2.6.30 > > open-iscsi version: 2.0.871 > > > Trace 1: SCSI from a write request to data written into pages > > > --> function pointer > > > sg_fops.write --> sg_write() > > Just so you know, this is the passthrough path. You are using some tools > like sg_utils or doing SG IO right? > > What I described might be a little different than this path. I was > describing the normal FS/Block layer code path (like when you do a > read()/write() to /dev/sda or to some file on a FS on /dev/sda). > > -- > You received this message because you are subscribed to the Google Groups > "open-iscsi" group. > To post to this group, send email to open-is...@googlegroups.com. > To unsubscribe from this group, send email to > open-iscsi+unsubscr...@googlegroups.com. > For more options, visit this group > athttp://groups.google.com/group/open-iscsi?hl=en. -- You received this message because you are subscribed to the Google Groups "open-iscsi" group. To post to this group, send email to open-is...@googlegroups.com. To unsubscribe from this group, send email to open-iscsi+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/open-iscsi?hl=en.